Stabilized petroleum product



alkyl derivatives,

Patented Dec. 2, 1943 2,264,893 F i Q E STABILIZED IPETRGLEUM PRQDEICTBernard H. Shoemaker,

W. Gaynor, t'lhicago,

Hammond, End, James Hit, and Lawson W.

Mixon, Hammond, ind, assignors to Standard No Drawing. Applicationgliipompany, Chicago, EL, a corporation of June 29, 1938,

Serial No. 216,582

16 Claims.

This invention. relates to improvements in stable mineral oils and moreparticularly to improvements in stable petroleum oils.

Many petroleum products, such as lubricating oils, electric insulatingoils, turbine oils, spindle oils, medicinal oils and the like arerefined by drastic chemical treatment and/or solvent extraction in orderto meet certain specifications. it has been observed that such drastictreatment seriously impairs certain properties of the oils, and mostseriously the property of resisting oxidation. Such drastically treatedoils are normally susceptible to autocatalytic oxidation with theattendant sludge formation, high acidity and/or possible peroxidedevelopment. Oils which are readily oxidized develop bad odors, highacidity and large amounts of oil insoluble oxidation products whichresult in poor demulsifying and insulating properties and render themunsuitable for their intended use.

Heretofore, the oxidation of oils of this type has been inhibited tosome extent by the addition thereto of from about 0.001% to about 0.25%of certain antioxidants such as the polyhydric phenols and the alkylderivatives thereof, for example catechol, tertiary butyl catechol,cresol, pyrogallol, hydroquinol, and the like, and the hydroxy condensedpoly ring compounds and their such as beta-naphthol, octylbeta-naphthol, amyl beta-naphthol, lauryl betanaphthol, alpha-naphthol,cetyl alpha-naphthol, butyl alpha-naphthol, amyl alpha-naphthol andother alkyl derivatives of alphaand beta-naphthols. Other inhibitorssuch as phenyl alphanaphthylamine, diphenylamine and butyl paraaminophenol have been used. Although these antioxidants are efiective toa degree, substantially complete inhibition is not obtained in manycases. For example, in some cases the inhibitor will retard sludging atelevated temperatures but will have little if any effect in inhibitingacidity formation.

It is the primary object of this invention to provide oils which are notsusceptible to high acidity development, are less susceptible tosludging than prior art products, and which do not have a high oxygenabsorption. It is another object of this invention to provide petroleumoils which have increased oxidation stability, which do not develop highacidity during service, and which retain their good demulsibility andinsulating properties. It is still another object of the presentinvention to provide a method of increasing the oxidation stability ofpetroleum oils.

We have discovered that the foregoing objects can be attained by addingto highly refined petroleum oils, alone or in combination with thehereinbefore mentioned antioxidants, small amounts, preferably fromabout 0.005% to about of high sulfur petroleum fractions. For the mosteffective results fractions from sulfur bearing crude oils should beemployed for this purpose, such as, for example, Winkler crude oil orother crude oils of the Winkler type. The dis- 5 tillates from Winklercrude oil contain from about 0.5% to about 2.5% sulfur, while theresiduums contain higher percentages of sulfur. A particular fractionwh'ch has been found effective is a Winkler crude oil distillate havinga gravity of from about 270 A. P. I. to about 27.4 A. P. 1., a Sayboltviscosity at 100 F. oi from about 50 seconds to about 80 seconds, and asulfur content of from about 0.75% to about 2.0%. Similarly, the abovetype of distillate which has been treated and percolated through fullersearth may be used.

We may also use the residue obtained in the distillation of highsulfur-containing light petroleum distillates, such as naphthas. -Anexample of such a residue is that obtained by doctor .sweetened Winklerstove distillate, which has a distillation range of from about 120 F. toabout 400 F., to obtain a residue which is from about 1.0% to about 2.0%of the total charge to the still. This residue has a sulfur content offrom about 0.5% to about 10.0%.

The efiectiveness of the fractions from high sulfur crude oils ininhibiting the oxidation of petroleum oils normally susceptible tooxidation is well illustrated by the following examples which areintended only to exemplify and not limit the scope of the invention:

Example I.The following samples A. Control (a highly refined transformeroil) B. Control+0.05% amyl beta-naphthol C. Control+0.5% high sulfurdistillate (-20% sulfur) D. Control+0.05% amyl beta-naphthol+0.5%

high sulfur distillate (Winkler) were heated at a temperature of about284 F. while exposed to the atmosphere, and at stated periods sampleswithdrawn and tested for sludge, color, and acidity. The acidity isreported in milligrams of KOH per cubic centimeter of oil.

' Acidity Color (N. P. A.) Time after fig aiter- Sample g g g 0 i o 6690 114 as 90 114 hrs hrs. hrs. hrs. hrs. hrs.

Hours A *ss 4 4}5 5-6 .54 .94 1.24 3.. *es 4 43.5 5-6 .49 .55 .94 c as3% 4 or .03 .10 .n 114 an ;4, or .05 .10 .09

Less than 66hrs.

It will benoted that the base oil and the base Oil.

contaiumg only amyl beta-naphthol develdevelopment was pronounced. Thebase oil containing Winkler distillate did not develop a high aciditybut is inferior in that sludge development occurred in a short period oftime. The oils containing both inhibitors. were more stable with respectto acidity development and sludge formation.

Example II.-ne method of obtaining an index of the oxidation stabilityof an oil is by the so-called Snyder life test which is determined bymaintaining about 500 cc. of the oil at a temperature of about 120 0.,and once every 24 hours withdrawing a cc. sample, cooling andcentrifuging the same for the purpose of determining when sludge firstappears. The life of the oil is the number of days the oil can bemaintained at 120 C. before visible sludge is formed. This test is fullydescribed in the A. S. T. M. Proceedings, volume 24, part I, p. 638(1924).

Submitting the following samples A. Control (highly refined transformeroil) 13. Control+0.05% amyl beta-naphthol C. Control+0.25% high sulfurdistillate (Winkler) D. Control+0.025%, amyl beta-naphthol+0.25%

high sulfur distillate to the Snyder life test, the following resultswere obtained:

Snyder life on test Days The above data show the marked increase in thesludge stability of a highly treated transformer oil, normallysusceptible to sludge formation, upon the addition of a small amount ofa light sulfur distillate, alone and in combination with anotherantioxidant, amyl beta-naphthol.

Example I1I.-The effectiveness of small amounts of high sulfur naphthabottoms in inhibiting oxidation is shown by the following data. The highsulfur naphtha bottoms were obtained by distilling a sweetened Winklerstove distillate which originally contained 0.09% mercaptan sulfur, to aresidue of about 1.5% of the charge to the still. The maximum stilltemperature was 300 F. The effectiveness of the high sulfur sweetenednaphtha bottoms, alone, and in combination with other inhibitors isshown by the following tests in which the following samples were tested:

A. Control (highly treated transformer oil) B. Control-k0.05% amylbeta-naphthol C. Control+0.02% high sulfur naphtha bottoms D.Control+0.05% amyl beta-naphthol+0. 02%.

high sulfur naphtha bottoms.

These samples were then submitted to the Snyder life test with thefollowing results:

on SnyieeSi; life Day:

I treated since we have Acidity mg. KOH

cc. oil

Oil Days Eqqqw The Snyder life test data show the beneficial effect ofsmall amounts of high sulfur naphtha bottoms in inhibiting the oxidationof highly refined oils, and the still marked inhibiting effect thereofwhen used in combination with other inhibitors such as amylbeta-naphthol.

- The high sulfur distillate used as oxidation inhibitors shouldpreferably be only lightly acid found that the inhibiting effect of thedistillates is greater with dlstiliates which have not been subjectedtoa drastic acid treatment. Using high sulfur distillates which had beentreated respectively with 1.0 pound of 104 /27.; acid per gallon of oil,and with 0.25 pound of 93% acid per gallon of oil, the following sampleswere prepared:

and subjected to a temperature of about 2w F. while exposed to theatmosphere. At stated intervals samples were withdrawnand tested. Theresults are tabulated below.

iftiii Color (N. P. A.) 5- Time aftercc. oil after Sample 33%;

formed 66 114 66 90 114 138 hrs. hrs. hrs. hrs. hrs. hrs. hrs.

Less than 66 hrs.

It will be observed that the distillate treated with 0.25 pound of 93%acid per gallon of distillate is more effective than the distillatetreated with one pound of IOU/ acid.

The distillates and naphtha bottoms from high sulfur crudes alone may beeffectively employed as oxidation inhibitors, although we prefer to usethem in combination with the hereinbefore mentioned inhibitors. While wehave described our invention by the way of certain specific embodimentsthereof, we do not limit the scope of the invention thereto, exceptinsofar as the same is defined by the appended claims.

We claim:

1. The method of inhibiting the oxidation of a highly refined viscoushydrocarbon oil which comprises adding thereto, in combination, a highsulfur-containing fraction from a high sulfur crude oil and an organiccompound selected from the class consisting of polyhydric phenols, alkylpolyhydric phenols, hydroxy condensed poly ring thol, alpha-naphthol,cetyl alpha-naphthol, cat

echol, butyl catechol and cresol, said addition agents being added insmall but suflicient quantitles to adequately inhibit the oxidation ofsaid highly refined viscous hydrocarbon oil.

3. The method of inhibiting the oxidation of a highly refined viscoushydrocarbon oil which comprises adding thereto, in combination, theresidue obtained by the distillation of a high sulfur-containingsweetened distillate within the naphtha distillation range, and anorganic compound selected from the class consisting of betanaphthol,octyl beta-naphthol, 'amyl beta-naphthol, alpha-naphthol, cetylalpha-naphthol, catechol, butyl catechol and cresol, said additionagents being added in small but sufilcient quantitles to adequatelyinhibit the oxidation of said highiyrefined viscous hydrocarbon oil.

4. The method of retarding the oxidation of a highly refined viscoushydrocarbon oil which comprises adding thereto, in combination, fromabout 0.5% to about 5% of a high sulfur distillate from asulfur-containing crude oil and from about 0.001% to about 0.25% of amylbetanaphthol. Y

5. The method of retarding the oxidation of a highly refined viscoushydrocarbon oil as defined in claim 3 in which the high sulfurdistillate' is a transformer oil distillate containing from about 0.5%to about 2.5% sulfur obtained from crude oils of the Winkler type.

6. The method of retarding oxidation of a highly refined viscoushydrocarbon oil which comprises adding thereto, in combination, fromabout 0.01% to about 2% of a high sulfur naphtha bottom and from about0.001% to about 0.25% of amyl beta-naphthol.

7. A method of retarding the oxidation of a highly refined viscoushydrocarbon oil as defined in claim 6 in which the high sulfur naphthabottoms is the residue obtained by distilling a sweetened Winkler stovedistillate to about a 1.5 bottom.

8. A highly refined viscous hydrocarbon oil con in combination, a highsulfur-containing fraction of a high sulfur crude oil and an organiccompound selected from the class consisting of polyhydric phenols, alkylpolyhydric phenols, hydroxy condensed polyring compounds and alkylhydroxy condensed poly ring compolmds in small but suflicient quantitiestoinhibit the oxidation or said highly refined viscous hydrocarbon oil.

' sweetened distillate within 9. A highly refined viscous hydrocarbonoil containing, in combination, small proportions of a high sulfurfraction of a high sulfur crude oil and an organic compound selectedfrom the class,

consisting of alpha-naphthols, beta-naphthols, catecols and cresols.

10. A highly refined viscous hydrocarbon oil containing from about 0.01%to about 5% of a petroleum distillate containing from about 0.5% toabout 2.5% sulfur and from about 0.001% to about 0.25% amylbeta-naphthol.

11. An oxidation resistant highly refined viscous hydrocarbon oilcontaining, in combination,

in small but oxidation inhibiting proportions a high sulfur containingnaphtha residue and amyl beta-naphthol.

12. An oxidation resistant transformer oil containing, in combination,from about 0.01% to about 5% of a transformer oil distillate containingfrom about 1.5% to about 2% sulfur and from about 0.001% to about 0.25%amyl betanaphthol.

13. A transformer oil highly resistant to oxidation containing fromabout 0.01% to about 2% of a high sulfur naphtha bottom and from about0.001% to about 0.25% 'amyl beta-naphthol.

14. The method of inhibiting the oxidation of a highly refined viscoushydrocarbon oil which comprises adding thereto, in combination, theresidue obtained by the distillation of a 'high sulfur-containingsweetened distillate within the naphtha distillation range, and anorganic compound selected from the class consisting of polyhydricphenols, alkyl polyhydric phenols, hydroxy condensed polyring compoundsand alkyl hydroxy condensed polyring compounds, said addition agentsbeing quantities to'lnhibit the oxidation of said highly refined viscoushydrocarbon oil.

15. A highly refined viscous hydrocarbon oil containing, in combination,the residue obtained by the distillation of a high sulfur-containingsweetened distillate within the naphtha distillation range, and anorganic compound selected from the class consisting of polyhydricphenols, alkyl polyhydric phenols, hydroxy condensed polyring compoundsand alkyl hydroxy con densed polyring compounds, said addition agentsbeing added in small but sufiicient quantities to inhibit theoxidation'oi said highly refined viscous hydrocarbon oil. j

' 16. A highly refined viscous hydrocarbon oil containing, incombination, the residue obtained by the distillation of a highsulfur-containing the naphtha distillation range, and an organiccompound selected from the class consisting of alpha naphthols, betanaphthols, catechols and cresols, said addition agents being added insmall but suflicient quantities to inhibit the oxidation of said highlyrefined viscous hydrocarbon oil. BERNARD H. 'SHOEMAKER. JAMES W. GAYNOR.LAWSON W. MJXON.

added in small but sufiicient 1

